Best way to earn bitcoin is trading or gamble.You need to have a good bankroll to make money from trading.
Honestly all of your suggested way to earn are all risky its better to join in campaign with better rank account.. so that you can earn best rate for every post you made here in our forum..
I don't suggest gambling to earn bitcoin but in trading if you have a knowledge how trading work because you can earn large amount of bitcoin if you are lucky to choose the best altcoin...